Japanese patent application 2000-184159 filed on Jun. 20, 2000 is hereby incorporated by reference in its entirety.
1. Field of the Invention
The present invention concerns an apparatus and a method for measuring a spherical article.
2. Description of the Related Art
Generally, athletic spherical articles such as ten-pin bowling balls, billiards balls, volleyball balls and soccer balls are established in size according to the respective standards.
For example, the ten-pin bowling balls are standardized such that the diameters should be within the range between the maximum permissible size of 218.281 mm and the minimum permissible size of 215.900 mm.
Measuring devices for accurately measuring the diameter of such a ten-pin bowling ball is independently owned by a ball manufacturer. Such a measuring device has never been used in any formal match.
One of the reasons is that the measuring device is extremely expensive and the size being so large that it is impossible to bring the device to a match.
Therefore, in a formal match, two metallic rings formed with circular opening of the maximum and minimum permissible sizes are provided. When a ball is passed through the two metallic rings, it is then judged whether or not that ball is within the permissible size range. If so, that ball may be used as a standardized ball in the formal match.
Although the use of these metallic rings can judge whether or not the ball meets the standard, however, it cannot measure the diameter of the ball accurately.
An object of the invention is to provide an apparatus and a method for measuring a spherical article, which can measure the diameter of a spherical article precisely and which can be carried easily.
To this end, (1) the present invention provides a an apparatus for measuring a spherical article comprising:
a first support arm having first and second ends, the first end being touchable to a first curve section at one end of a diametrical line of a spherical article to be measured, the second end being locatable spaced apart from and opposite to a second curve section at the other end of the diametrical line;
a second support arm provided on the first support arm and having a third end touchable to a third curve section on the spherical article; and
a size detector provided on the second end of the first support arm and being touchable to the second curve section.
According to the present invention, the first end of the first support arm and the third end of the second support arm are brought into contact with the spherical article to be supportive when the first and second support arms are applied to the spherical article. In this position, the first end of the first support arm and the size detector on the second end of the first support arm will be located on the diametrical line of the spherical article. Thus, the diameter of the spherical article sandwiched therebetween can be measured accurately by the size detector. In addition, this spherical-article measuring apparatus is simplified in structure and more easily carried.
(2) In this spherical-article measuring apparatus, the size detector may detect whether or not a size of the spherical article is within a permissible size range.
Such an arrangement ensures and facilitates finding whether or not the diameter of the spherical article is within the range between the maximum and minimum permissible sizes.
(3) This spherical-article measuring apparatus may further comprise:
a first spherical-article touching portion extending from the first end of the first support arm;
a second spherical-article touching portion extending from a portion of the first end of the first support arm at a position rotated by an angle greater than or equal to 90 degrees about a central point of the spherical article from the first end of the first support arm; and
a third spherical-article touching portion extending from the third end of the second support arm.
In such an arrangement, three spherical-article touching portions formed on the first and second support arms can support the first and second support arms so that the spherical article can be supported more stably compared to the case in which the spherical article is brought into direct contact with the first and second support arms.
(4) In this spherical-article measuring apparatus, each of the spherical-article touching portions may have a spherical-article touching surface which extends two-dimensionally and at least corresponds to the permissible size range of the spherical article.
Such an arrangement ensures the detection of the diameter of the spherical article since each of the spherical-article touching surfaces can positively engage with the corresponding curve section of the spherical article on the diametrical line thereof even though the spherical article is of the maximum or minimum permissible size.
(5) In this spherical-article measuring apparatus, the size detector may have a dial gauge and a measuring element extending from the second end of the first support arm toward the second curve section of the spherical article.
Such an arrangement enables the dial gauge to measure the diameter of the spherical article accurately.
(6) In this spherical-article measuring apparatus, the measuring element may have a measuring surface at a tip end thereof extending two-dimensionally and at least corresponding to the permissible size range of the spherical article.
Such an arrangement ensures the detection of the diameter of the spherical article since the measuring surface of the measuring element can always be engaged with the corresponding curve section of the spherical article on the diametrical line thereof even though the spherical article is of the maximum or minimum permissible size.
(7) In this spherical-article measuring apparatus, the dial gauge may measure the diametrical line of the spherical article based on the minimum permissible size.
Such an arrangement enables the dial gauge to measure how much larger the spherical article is compared to the minimum permissible size.
(8) In this spherical-article measuring apparatus, the dial gauge may measure the diametrical line of the spherical article based on the maximum permissible size.
Such an arrangement enables the dial gauge to measure how much smaller the spherical article is compared to the maximum permissible size.
(9) This spherical-article measuring apparatus may further comprise a datum setter for setting a reference diameter size of the spherical article. In this spherical-article measuring apparatus, the dial gauge may set a reference value corresponding to the reference diametrical size by holding the datum setter between the first end of the first support arm and the measuring element of the dial gauge.
Such an arrangement enables the datum setter to easily set the reference value of the dial gauge together with the reference diameter size of the spherical article.
(10) In this spherical-article measuring apparatus, the spherical article may be a ten-pin bowling ball.
Such an arrangement ensures and facilitates the measurement of the diameter of the ten-pin bowling ball.
(11) In this spherical-article measuring apparatus, the second support arm may be located to be orthogonal to the first support arm.
(12) In this spherical-article measuring apparatus, the third end may be located at an end of a radial line orthogonal to the diametrical line of the spherical article.
(13) The present invention further provides a method for measuring a spherical article comprising the steps of:
specifying a base point to be measured on the spherical article;
setting three parting lines dividing the spherical article into eight portions based on the base point to be measured;
setting a plurality of intersection points of the three parting lines; and
measuring a diametrical line of the spherical article with the apparatus as defined in claim 1,
wherein the size detector and the first end of the first support arm touches two of the plurality of intersection points at both ends of the diametrical line of the spherical article.
According to the present invention, a plurality of intersection points on the three parting lines dividing the spherical article into eight portions are set based on the base point to be measured. The intersection points are used to measure the diameter of the spherical article. Thus, it is possible to measure the diameter of the spherical article on the parting lines accurately. In addition, the roundness of the spherical article can be measured.
(14) In this spherical-article measuring method, the three parting lines may be set by lines imaged by intersection of a surface of the spherical article and three planes, the three planes orthogonally crossing each other, each of the three planes passing through a central point of the spherical article.
(15) In this spherical article measuring method, the plurality of intersection points of the three parting lines may be set at ends of the three orthogonal diametrical lines.
(16) This spherical article measuring method may measure each of the three diametrical lines.
(17) The present invention further provides a method for measuring a spherical article comprising the steps of:
setting first and second points at opposite ends of a diametrical line in any position on a spherical article to be measured;
positioning the first end of the apparatus as defined in claim 1 in touch with a first curve section at the first point of the spherical article;
positioning the second end of the apparatus as defined in claim 1 spaced apart from and opposite to a second curve section at the second point of the spherical article; and
positioning the third end of the second support arm of the apparatus as defined in claim 1 in touch with a third curve section of the spherical article; and
positioning the size detector of the apparatus as defined in claim 1 in touch with the second curve section to measure a spacing between the first and second points.
(18) This spherical-article measuring method may further comprise the steps of:
setting third and fourth points at opposite ends of a diametrical line in a second position of the spherical article;
positioning the first end in touch with a third curve section at the third point of the spherical article;
positioning the second end spaced apart from and opposite to a fourth curve section at the fourth point of the spherical article; and
positioning the size detector in touch with the fourth curve section to measure a spacing between the third and fourth points.
(19) This spherical-article measuring method may further comprise the steps of:
setting fifth and sixth points at opposite ends of a diametrical line in a third position of the spherical article;
positioning the first end in touch with a fifth curve section at the fifth point of the spherical article;
positioning the second end spaced apart from and opposite to a sixth curve section at the sixth point of the spherical article; and
positioning the size detector in touch with the sixth curve section to measure a spacing between the fifth and sixth points.
(20) This spherical-article measuring method may further comprise the steps of:
specifying a base point to be measured on the spherical article;
setting three parting lines dividing the spherical article into eight portions based on the base point to be measured, the three parting lines being imaged by intersection of a surface of the spherical article and three planes, the three planes orthogonally crossing each other, each of the three planes passing through a central point of the spherical article;
setting a plurality of intersection points on the three parting lines; and
selecting any pair of intersection points from the intersection points.